A fuel supply device, which includes a tank lid fixed to a fuel tank, has been widely used.
In one such fuel supply device disclosed in the patent literature 1, an opening portion of the fuel tank is closed with the tank lid such that a lid front surface of the tank lid is exposed to the outside of the fuel tank. The lid front surface of the tank lid is made of resin that is acid resistant, so that durability of the tank lid is improved.
However, in the fuel supply device disclosed in the patent literature 1, the acid resistant resin is layered over the base resin through double-shot molding to form the tank lid. In the case of this type of manufacturing method of the tank lid, when the structure of the tank lid is complicated due to, for example, a projection of a connector that surrounds metal terminals, a primary molded product may be easily damaged at the time of secondary molding, or there may be an unavoidable incidence of that a portion of the tank lid cannot be formed as a secondary product. Furthermore, particularly, in the case where the primary molded product can be easily damaged, it is difficult to manage the injection pressure control and the contraction pressure control of the resin at the time of secondary molding. Therefore, the productivity of the tank lid is disadvantageously deteriorated.
In view of the above disadvantage, the inventors of the present application have studied a technique that improves not only the durability of the tank lid but also the productivity of the tank lid by coating of an acid resistant film on at least the lid front surface of the tank lid. As a result of the study, the following need is found. That is, in a case where the tank lid includes the connector that has the bottomed tubular inner surface, which surrounds the metal terminals, it is required to form a resin coating film, which is acid resistant against an acidic liquid located at the outside of the fuel tank and is dielectric, on the connector while film thickness variations of the resin coating film is kept to be small. This is due to the following reason. That is, for example, in a case where the resin coating film is formed by an ordinary spray coating technique, due to a surface tension of a liquid paint and blowback of the liquid paint at the time of spraying the liquid paint, the film thickness of the resin coating film is reduced at an inner corner portion of the bottomed tubular inner surface of the connector and an outer corner portion of an outer peripheral surface of the connector in comparison to the rest of the connector, so that the acid resistance and the dielectricity of the resin coating film are deteriorated at the inner corner portion of the bottomed tubular inner surface of the connector and the outer corner portion of the outer peripheral surface of the connector.